Archives of Foundry Engineering

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Description

Archives of Foundry Engineering continues the publishing activity
started by Foundry Commission of the Polish Academy of Sciences (PAN) in
Katowice in 1978. The initiator of it was the first Chairman Professor
Dr Eng. Wacław Sakwa – Corresponding Member of PAN, Honorary Doctor of
Czestochowa University of Technology and Silesian University of
Technology. This periodical first name was „Solidification of Metals and
Alloys” , and made possible to publish the results of works achieved in
the field of the Basic Problems Research Cooperation. The subject of
publications was related to the title of the periodical and concerned
widely understand problems of metals and alloys crystallization in a
casting mold. In 1978-2000 the 44 issues have been published. Since 2001
the Foundry Commission has had patronage of the annually published
“Archives of Foundry” and since 2007 quarterly published “Archives of
Foundry Engineering”. Thematic scope includes scientific issues of
foundry industry:

Abstract

Liquid AI -Si alloys are usually given special treatments before they
are cast to obtain finer or modified matrix and eutectic structures,
leading to improved proper ties. For many years, sodium additions to
hypoeutectic and eutectic AI -Si melts have been recognized as the most
effective method of modifying the eutectic morphology, although most of
the group IA or IIA elements have significant effects on the eutectic s
tructure. Unfortunately, many of these approaches also have associated
several founding difficulties, such as fading, forming dross in presence
of certain alloying elements, reduced fluidity, etc. ln recent years,
antimony additions to AI -Si castings have attracted considerable
attention as an alternative method of refining the eutectic structure.
Such additions eliminate many of the difficulties listed above and
provide permanent (i.e. non -fading) refining ability. In this paper,
the authors summarize work on antimony treatment of Al -Si based alloys.

Abstract

The paper presents results of calorimetric studies of foundry nickel
superalloys: IN100, IN713C, Mar - M247 and ŻS6 U. Particular attention
was paid to determination of phase transiti ons temperatures during
heating and cooling. The samples were heated to a temperature of 1500°C
with a rate of 10°C ⋅ min – 1 and then held at this temperature for 5
min. After a complete melting, the samples were cooled with the same rat
e. Argon with a purity of 99.99% constituted the protective atmosphere.
The sample was placed in an alundum crucible with a capacity of 0.45 cm
3 . Temperature and heat calibration was carried out based on the mel
ting point of high- purity Ni. The tests were carried out by the
differential scanning calorimetry (DSC) using a Multi HTC high
-temperature calorimeter from Setaram. Based on the DSC curves, the
following temperatures were determined: solidus and liquidus,
dissolution and precipitation of the γ ’ phase, MC carbides and melting
of the γ ’ /γ eutectic. In the temperature range of 100 -1100°C,
specific heat capacity of the investigated superalloys was determined.
It was found that the IN713C and IN100 alloys exhibit a higher specific
heat while compared to the Mar - M247 and ŻS6 U alloys.

Abstract

The paper deals with susceptibility of nodular cast iron with ferritic
-pearlitic matrix on cavitation erosion . Cavitation tests were carried
out with the use of a cavitation erosion vibratory apparatus employing a
vibration exciter operated at frequency of 20 kHz. The study allowed to
determine the sequence of subsequent stages in which microstr ucture of
cast iron in superficial regions is subject to degradation. The first
features to be damaged are graphite precipitates. The ferritic matrix of
the alloy turned out to be definitely less resistant to cavitation
erosion compared to the pearlitic matrix component.

Abstract

The modified surface layers of Mg enriched with Al and Si were
fabricated by thermochemical treatment. The substrate material in
contact with an Al + 20 wt.% Si powder mixture was heated to 445ºC for
40 or 60 min. The microstructure of the layers was examined by OM and
SEM. The chemical composition of the layer and the distribution of
elements were determined by energy dispersive X-ray spectroscopy (EDS).
The experimental results show that the thickness of the layer is
dependent on the heating time. A much thicker layer (1 mm) was obtained
when the heating time was 60 min than when it was 40 min (600 μm). Both
layers had a non-homogeneous structure. In the area closest to the Mg
substrate, a thin zone of a solid solution of Al in Mg was detected. It
was followed by a eutectic with Mg17Al12and a solid solution of Al in
Mg. The next zone was a eutectic with agglomerates of Mg2Si phase
particles; this three-phase structure was the thickest. Finally, the
area closest to the surface was characterized by dendrites of the
Mg17Al12phase. The microhardness of the modified layer increased to
121-236 HV as compared with 33-35 HV reported for the Mg substrate.

Abstract

Cast irons are good examples of materials which are more sensitive to
chemical composition and production conditions. In this research to
improve casting quality, solidification and nucleation process in grey
cast iron was investigate. In particular, attempts have been made to
rationalize variation in eutectic cells with nucleation sites and
eutectic solidification undercooling. Four castings with different
diameter and similar chemical composition and pouring temperature and
different inoculant percentage was casted. The cooling curve and maximum
and minimum undercooling for each castings was measured. Also optical
metallography and image analyzer has been used to determine the average
eutectic cells diameter, and linear and surface densities, and volume
density was calculated. The results of this research show a competitive
behavior between nucleation sites and eutectic undercooling. Higher
nucleation sites and higher eutectic undercooling cause higher eutectic
cell density. But increasing nucleation sites by introducing inoculants
to molten metal, is accompanied with reduction in eutectic undercooling.
It means that inoculation and undercooling have opposite effect on each
other. So, to achieve maximum cell density, it is necessary to create an
optimization between these parameters.

Abstract

The paper presents an approach of numerical modelling of alloy
solidification in permanent mold and transient heat transport between
the casting and the mold in two-dimensional space. The gap of
time-dependent width called "air gap", filled with heat conducting
gaseous medium is included in the model. The coefficient of thermal
conductivity of the gas filling the space between the casting and the
mold is small enough to introduce significant thermal resistance into
the heat transport process. The mathematical model of heat transport is
based on the partial differential equation of heat conduction written
independently for the solidifying region and the mold. Appropriate
solidification model based on the latent heat of solidification is also
included in the mathematical description. These equations are
supplemented by appropriate initial and boundary conditions. The
formation process of air gap depends on the thermal deformations of the
mold and the casting. The numerical model is based on the finite element
method (FEM) with independent spatial discretization of interacting
regions. It results in multi-mesh problem because the considered regions
are disconnected.

Abstract

The paper presents an application of advanced data-driven (soft) models
in finding the most probable particular causes of missed ductile iron
melts. The proposed methodology was tested using real foundry data set
containing 1020 records with contents of 9 chemical elements in the iron
as the process input variables and the ductile iron grade as the output.
This dependent variable was of discrete (nominal) type with four
possible values: ‘400/18’, ‘500/07’, ‘500/07 special’ and
‘non-classified’, i.e. the missed melt. Several types of classification
models were built and tested: MLP-type Artificial Neural Network,
Support Vector Machine and two versions of Classification Trees. The
best accuracy of predictions was achieved by one of the Classification
Tree model, which was then used in the simulations leading to conversion
of the missed melts to the expected grades. Two strategies of changing
the input values (chemical composition) were tried: content of a single
element at a time and simultaneous changes of a selected pair of
elements. It was found that in the vast majority of the missed melts the
changes of single elements concentrations have led to the change from
the non-classified iron to its expected grade. In the case of the three
remaining melts the simultaneous changes of pairs of the elements’
concentrations appeared to be successful and that those cases were in
agreement with foundry staff expertise. It is concluded that utilizing
an advanced data-driven process model can significantly facilitate
diagnosis of defective products and out-of-control foundry processes.

Abstract

The present investigation focuses on the study of the influence of
titanium inoculation on tribological properties of High Chromium Cast
Iron. Studies of tribological properties of High Chromium Cast Iron, in
particularly the wear resistance are important because of the special
application of this material. High Chromium Cast Iron is widely used for
parts that require high wear resistance for example the slurry pumps,
brick dies, several pieces of mine drilling equipment, rock machining
equipment, and similar ones. Presented research described the effects of
various amounts of Fe-Ti as an inoculant for wear resistance. The
results of wear resistance were collated with microstructural analysis.
The melts were conducted in industrial conditions. The inoculation was
carried out on the stream of liquid metal. The following amount of
inoculants have been used; 0.17% Fe-Ti, 0.33% Fe-Ti and 0.66% Fe-Ti. The
tests were performed on the machine type MAN. The assessment of wear
resistance was made on the basis of the weight loss. The experimental
results indicate that inoculation improve the wear resistance. In every
sample after inoculation the wear resistance was at least 20% higher
than the reference sample. The best result, thus the smallest wear loss
was achieved for inoculation by 0.66% Fe-Ti. There is the correlation
between the changing in microstructure and wear resistance. With greater
amount of titanium the microstructure is finer. More fine carbides do
not crumbling so quickly from the matrix, improving the wear resistance.

Abstract

The paper presents the results of preliminary research on the use of
silica sands with hydrated sodium silicate 1.5% wt. of binder for the
performance of eco-friendly casting cores in hot-box technology. To
evaluate the feasibility of high quality casting cores performed by the
use of this method, the tests were made with the use of a semiautomatic
core shooter using the following operating parameters: initial shooting
pressure of 6 bar, shot time 4 s and 2 s, core-box temperature 200, 250
and 300 °C and core heating time 30, 60, 90 and 150 s. Matrixes of the
moulding sands were two types of high-silica sand: fine and medium.
Moulding sand binder was a commercial, unmodified hydrated sodium
silicate having a molar module SiO2/Na2O of 2.5. In one shot of a
core-shooter were made three longitudinal samples (cores) with a total
volume of about 2.8 dm3. The samples thus obtained were subjected to an
assessment of the effect of shooting parameters, i.e. shooting time,
temperature and heating time, using the criteria: core-box fill rate,
bending strength (RgU), apparent density and surface quality after
hardening. The results of the trials on the use of sodium silicate
moluding sands made it possible to further refine the conditions of next
research into the improvement of inorganic warm-box/hot-box technology
aimed at: reduction of heating temperature and shot time. It was found
that the performance of the cores depends on the efficiency of the
venting system, shooting time, filling level of a shooting chamber and
grains of the silica matrix used.

Abstract

A large number of defects of castings made in sand moulds is caused by
gases. There are several sources of gases: gases emitted from moulds,
cores or protective coatings during pouring and casting solidification;
water in moulding sands; moisture adsorbed from surroundings due to
atmospheric conditions changes. In investigations of gas volumetric
emissions of moulding sands amounts of gases emitted from moulding sand
were determined - up to now - in dependence of the applied binders, sand
grains, protective coatings or alloys used for moulds pouring. The
results of investigating gas volumetric emissions of thin-walled sand
cores poured with liquid metal are presented in the hereby paper. They
correspond to the surface layer in the mould work part, which is
decisive for the surface quality of the obtained castings. In addition,
cores were stored under conditions of a high air humidity, where due to
large differences in humidity, the moisture - from surroundings - was
adsorbed into the surface layer of the sand mould. Due to that, it was
possible to asses the influence of the adsorbed moisture on the gas
volumetric emission from moulds and cores surface layers by means of the
new method of investigating the gas emission kinetics from thin moulding
sand layers heated by liquid metal. The results of investigations of
kinetics of the gas emission from moulding sands with furan and alkyd
resins as well as with hydrated sodium silicate (water glass) are
presented. Kinetics of gases emissions from these kinds of moulding
sands poured with Al-Si alloy were compared.

Abstract

The aim of the current study was to examine the structure of an alloy
treated at various temperatures up to 2,000–2,100 °C. Among research
techniques for studying alloy structure there were the electron and
optical microstructure, X-ray structure, and spectral analysis, and for
studying the developed furnace geometric parameters the authors employed
mathematical modeling method. The research was performed using aluminum
smelting gas-fired furnaces and electric arc furnaces. The objects of
the study were aluminum alloys of the brand AK7p and AK6, as well as
hydrogen and aluminum oxide in the melt. For determining the hydrogen
content in the aluminum alloy, the vacuum extraction method was
selected. Authors have established that treatment of molten aluminum
alloy in contact with carbon melt at high temperatures of 2,000–2,100 °C
has resulted in facilitating reduction of hydrogen and aluminum oxide
content in the melt by 40-43% and 50-58%, respectively, which is
important because hydrogen and aluminum oxide adversely affect the
structure and properties of the alloy. Such treatment contributes to the
formation of the extremely fine-grained microstructure of aluminum alloy.

Abstract

In this article, there were presented results of research on influence
of reclamation process on the ecological quality of reclaim sand with
furan resin used in nonferrous foundry. The quality of reclaimed sand is
mainly define by two group of chemical substances from elution of
reclaimed sand: Dissolves Organic Carbon (DOC) and Total Dissolves
Solids (TDS). Reclaimed sand used in test was prepared in experimental
thermal reclaimer and mechanical vibration reclaimer REGMAS installed in
Faculty of Foundry Engineering at University of Science and Technology
in Krakow. The reference point is molding sand shaking out and crumble
in jaw crusher. Test of elution was made in acreditation laboratory in
Center For Research and Environmental Control in Katowice up to the
standard with Dissolves Organic Carbon (DOC) - PN-EN 1484:1999; Total
Dissolves Solids (TDS) - PN-EN 15216:2010. The standard for elution test
is PN-EN 12457- 4:2006. Except that we were made loss of ignition test,
to check how many resin was rest on sand grains.

Abstract

The investigation results of the kinetics of binding ceramic moulds,
in dependence on the solid phase content in the liquid ceramic slurries
being 67, 68 and 69% - respectively, made on the basis of the aqueous
binding agents Ludox AM and SK. The ultrasonic method was used for
assessing the kinetics of strengthening of the multilayer ceramic mould.
Due to this method, it is possible to determine the ceramic mould
strength at individual stages of its production. Currently
self-supporting moulds, which must have the relevant strength during
pouring with liquid metal, are mainly produced. A few various factors
influence this mould strength. One of them is the ceramic slurry
viscosity, which influences a thickness of individual layers deposited
on the wax model in the investment casting technology. Depositing of
layers causes increasing the total mould thickness. Therefore, it is
important to determine the drying time of each deposited layer in order
to prevent the mould cracking due to insufficient drying of layers and
thus the weakening of the multilayer mould structure.

Abstract

The paper presents a novel Iterated Local Search (ILS) algorithm to
solve multi-item multi-family capacitated lot-sizing problem with setup
costs independent of the family sequence. The model has a direct
application to real production planning in foundry industry, where the
goal is to create the batches of manufactured castings and the sequence
of the melted metal loads to prevent delays in delivery of goods to
clients. We extended existing models by introducing minimal utilization
of furnace capacity during preparing melted alloy. We developed simple
and fast ILS algorithm with problem-specific operators that are
responsible for the local search procedure. The computational
experiments on ten instances of the problem showed that the presence of
minimum furnace utilization constraint has great impact on economic and
technological conditions of castings production. For all test instances
the proposed heuristic is able to provide the results that are
comparable to state-of-the art commercial solver.

Abstract

A mathematical model of austenite - bainite transformation in
austempered ductile cast iron has been presented. The model is based on
a model developed by Bhadeshia [1, 2] for modelling the bainitic
transformation in high-silicon steels with inhibited carbide
precipitation. A computer program has been developed that calculates the
incubation time, the transformation time at a preset temperature, the
TTT diagram and carbon content in unreacted austenite as a function of
temperature. Additionally, the program has been provided with a module
calculating the free energy of austenite and ferrite as well as the
maximum driving force of transformation. Model validation was based on
the experimental research and literature data. Experimental studies
included the determination of austenite grain size, plotting the TTT
diagram and analysis of the effect of heat treatment parameters on the
microstructure of ductile iron. The obtained results show a relatively
good compatibility between the theoretical calculations and experimental
studies. Using the developed program it was possible to examine the
effect of austenite grain size on the rate of transformation.

Abstract

Mg-0.5Si-xSn (x=0.95, 2.9, 5.02wt.%) alloys were cast and extruded at
593K (320 ºC) with an extrusion ratio of 25. The microstructure and
mechanical properties of as-cast and extruded test alloys were
investigated by OM, SEM, XRD and tensile tests. The experimental results
indicate that the microstructure of the Mg-0.5Si-xSn alloys consists of
primary α-Mg dendrites and an interdendritic eutectic containing α-Mg,
Mg2Si and Mg2Sn. There is no coarse primary Mg2Si phase in the test
alloys due to low Si content. With the increase in the Sn content, the
Mg2Si phase was refined. The shape of Mg2Si phase was changed from
branch to short bar, and the size of them were reduced. The ultimate
tensile strength and yield strength of Mg-0.52Si-2.9Sn alloy at the
temperature of 473K (200 ºC) reach 133MPa and 112MPa respectively.
Refined eutectic Mg2Si phase and dispersed Mg2Sn phase with good
elevated temperature stability are beneficial to improve the elevated
temperature performance of the alloys. However, with the excess addition
of Sn, large block-like Mg2Sn appears around the grain boundary leading
to lower mechanical properties.

Abstract

In this study, low-carbon cast steel was reinforced with TiC by SHS-B
method, also known as combustion synthesis during casting method. The
composite zone was then subjected to surface remelting by Gas Tungsten
Arc Welding (GTAW) method. The remelting operation was realized
manually, at 150 A current magnitude. Microstructure, phase composition
and hardness of remelted zone were investigated. XRD results reveal that
the phases of the composite zone in initial state consist of TiC and
Feα. Surface remelting resulted in formation of thick layers containing
TiC carbides, Feα and Feγ. Microstructural examination has shown strong
refinement of titanium carbides in remelted zone and complete
dissolution of primary titanium carbides synthetized during casting. The
average diameter of carbides was below 2 μm. The structural changes are
induced by fast cooling which affects crystallization rate. The hardness
(HV30) of the remelted layer was in the range between 250 HV and 425 HV,
and was lower than hardness in initial state.

Abstract

Mg-0.5Si-xSn (x=0.95, 2.9, 5.02wt.%) alloys were cast and extruded at
593K (320 o C) with an extrusion ratio of 25. The microstructure and
mechanical properties of as-cast and extruded test alloys were
investigated by OM, SEM, XRD and tensile tests. The experimental results
indicate that the microstructure of the Mg-0.5Si-xSn alloys consists of
primary α-Mg dendrites and an interdendritic eutectic containing α-Mg,
Mg2Si and Mg2Sn. There is no coarse primary Mg2Si phase in the test
alloys due to low Si content. With the increase in the Sn content, the
Mg2Si phase was refined. The shape of Mg2Si phase was changed from
branch to short bar, and the size of them were reduced. The ultimate
tensile strength and yield strength of Mg-0.52Si-2.9Sn alloy at the
temperature of 473K (200 o C) reach 133MPa and 112MPa respectively.
Refined eutectic Mg2Si phase and dispersed Mg2Sn phase with good
elevated temperature stability are beneficial to improve the elevated
temperature performance of the alloys. However, with the excess addition
of Sn, large block-like Mg2Sn appears around the grain boundary leading
to lower mechanical properties.

Abstract

In this study, rubber seed/shea butter oil was used to formulate core
oil. The formulated core oil was characterised. D-optimal mixture design
was used for multi response optimisation of the functional properties of
rubber seed-shea butter coil oil. Desirable values for some responses
might be obtained from a factor combination while for others responses
not so desirable values. Through multiple response optimisations, a
factor setting that gives the desirable values for all responses was
obtained. The selected optimum mixture setting for the formulated core
oil is 65.937% Rubber seed and 34.063% Shea butter oil at desirability
of 0.924. Under the optimum condition the functional properties of the
core oil was found to be 39.57KN/M2, 626.85KN/M2, 36.63KN/M2,
593.906KN/M2, 412.605 and 167.309s for Green Compressive Strength, Dry
Compressive Strength, Green Tensile Strength, Dry Tensile Strength,
Permeability and Collapsibility respectively. The optimum conditions
were validated with less than 0.2% error. The functional properties of
the formulated core oil was compared to the functional properties of
linseed core oil. It was found that rubber seed-shea butter core oil can
be used for producing cores suitable for Aluminium casting.

Abstract

In this work, T-shaped mould design was used to generate hot spot and
the effect of Sr and B on the hot tearing susceptibility of A356 was
investigated. The die temperature was kept at 250o C and the pouring was
carried out at 740o C. The amonut of Sr and B additions were 30 and 10
ppm, respectively. One of the most important defects that may exist in
cast aluminium is the presence of bifilms. Bifilms can form by the
surface turbulence of liquid metal. During such an action, two unbonded
surfaces of oxides fold over each other which act as a crack. Therefore,
this defect cause many problems in the cast part. In this work, it was
found that bifilms have significant effect over the hot tearing of A356
alloy. When the alloy solidifies directionally, the structure consists
of elongated dendritic structure. In the absence of equiaxed dendrites,
the growing tips of the dendrites pushed the bifilms to open up and
unravel. Thus, leading to enlarged surface of oxide to become more
harmful. In this case, it was found that these bifilms initiate hot
tearing.

Abstract

The effects of silica additive (Poraver) on selected properties of
BioCo3 binder in form of an aqueous poly(sodium acrylate) and dextrin
(PAANa/D) binder were determined. Based on the results of the
thermoanalytical studies (TG-DTG, FTIR, Py-GC/MS), it was found that the
silica additive results in the increase of the thermostability of the
BioCo3 binder and its contribution does not affect the increase in the
level of emissions of organic destruction products. Compounds from group
of aromatic hydrocarbons are only generated in the third set temperature
range (420-838°C). The addition of silicate into the moulding sand with
BioCo3 causes also the formation of a hydrogen bonds network with its
share in the microwave radiation field and they are mainly responsible
for maintaining the cross-linked structures in the mineral matrix
system. As a consequence, the microwave curing process in the presence
of Poraver leads to improved strength properties of the moulding sand
( ). The addition of Poraver's silica to moulding sand did not
alter the permeability of the moulding sand samples, and consequently
reduced their friability. Microstructure investigations (SEM) of
microwave-cured samples have confirmed that heterogeneous sand grains
are bonded to one another through a binder film (bridges).

Abstract

Nickel-based alloys are widely used in industries such as the aircraft
industry, chemicals, power generation, and others. Their stable
mechanical properties in combination with high resistance to aggressive
environments at high temperatures make these materials suitable for the
production of components of devices and machines intended for operation
in extremely difficult conditions, e.g. in aircraft engines. This paper
presents the results of thermal and mechanical tests performed on
precision castings made of the Inconel 713C alloy and intended for use
in the production of low pressure turbine blades. The tests enabled the
determination of the nil strength temperature (NST), the nil ductility
temperature (NDT), and the ductility recovery temperature (DRT) of the
material tested. Based on the values obtained, the high temperature
brittleness range (HTBR) and the hot cracking resistance index were
determined. Metallographic examinations were conducted in order to
describe the cracking mechanisms. It was found that the main cracking
mechanism was the partial melting of grains and subsequently the rupture
of a thin liquid film along crystal boundaries as a result of
deformation during crystallisation. Another cracking mechanism
identified was the DDC (Ductility Dip Cracking) mechanism. The results
obtained provide a basis for improving precision casting processes for
aircraft components and constitute guidelines for designers, engineers,
and casting technologists.

Abstract

The study discusses the issues connected with the production of
thin-walled ceramic slurry in the replicast cs technology. In the
ceramic mould production process, a special role is played by the liquid
ceramic slurry used to produce the first layer of the mould. The study
examines selected technological properties of liquid ceramic slurries
used to produce moulds in the replicas cs technology. The ceramic
slurries for the tests were prepared based on the binders Ludox Px30 and
Sizol 030, enriched with Refracourse flour. The wettability of the
pattern's surface by the liquid ceramic slurry and the dependence of the
apparent viscosity on the ceramic flour content in the mixture were
determined. The wettability of the pattern surface by the liquid ceramic
slurry was determined based on the measurement of the wetting angle. The
angle was determined by means of an analysis of the computer image
obtained with the use of a CDC camera.

Abstract

Emergence of new designs for internal combustion engines resulted in a
necessity to search for new materials which will rise to excessive
technological requirements under operating conditions of modern internal
combustion engines of up to 150 kW. Focusing only on material
properties, theoretically existing alloys should meet presents
requirements. More importantly, existing materials are well fitted to
the entire crank-piston system. Thus, there is a need for a more
thorough examination of these materials. The paper presents studies on
determination of coefficient of friction μ and wear for the A390.0 alloy
modified with AlTi5B master alloy combined with EN GJL-350 cast iron.
The characteristics of a T-11 tribological tester (pin on disc) used for
the tests, as well as the methodology of the tribological tests, were
described. Also, the analysis of the surface distribution of elements
for the pin and the disc was presented. The studies were realized in
order to find whether the analyzed alloy meets the excessive
requirements for the materials intended for pistons of modern internal
combustion engines. The results show that the A390.0 alloy can only be
applied to a load of 1.4 MPa. Above this value was observed destructive
wear, which results in the inability to use it in modern internal
combustion engines.

Abstract

Metallographic investigations and a computer simulation of stresses in a
gravity die-casting bushing were performed. Simulation of the casting
process, solidification of the thick-walled bushing and calculations of
the stress was performed using MAGMA5.3 software. The size variability
of phases κIIaffecting the formation of phase stresses σf, depending on
the location of the metallographic test area, was identified. The
distribution of thermal σtand shrinkage stresses σs, depending on the
location of the control point SC in the bushing's volume, was estimated.
Probably the nature of these stresses will change slightly even after
machining. This can cause variations in operating characteristics
(friction coefficient, wear). Due to the strong inhomogeneity of the
stress distribution in the bushing's casting, it is necessary to perform
further tests of the possibility to conduct thermal treatment
guaranteeing homogenization of the internal stresses in the casting, as
well as to introduce changes in the bushing's construction and the
casting technology. The paper presents the continuation of the results
of research aimed at identifying the causes of defects in the
thick-walled bushing, die-casting made of CuAl10Fe5Ni5Cr aluminium
bronze.

Abstract

The paper attempts to analyze distortions of cast iron and cast steel
rings, after heat treatment cycles. The factors influencing distortion
are: chemical composition of material, sample geometry, manufacturing
process, hardenability, temperature and heat treatment method. Standard
distortion tests are performed on C-ring samples. We selected a
ring-model, which approximate the actual part, so that findings apply to
gear rings. Because distortion depends on so many variables, this study
followed strictly defined procedures. The research was started by
specifying the appropriate geometry of the samples. Then, the heat
treatment was conducted and samples were measured again. The obtained
results allow to determine the value of the resulting distortion and
their admissibility. The research will be used to evaluate the
possibility of using the material to produce parts of equipment operated
under extreme load conditions.

Abstract

Owing to its properties, metallic foams can be used as insulation
material. Thermal properties of cast metal-ceramic composite foams have
applications in transport vehicles and can act as fire resistant and
acoustic insulators of bulkheads. This paper presents basic thermal
properties of cast and foamed aluminum, the values of thermal
conductivity coefficient of selected gases used in foaming composites
and thermal capabilities of composite foams (AlSi11/SiC). A certificate
of non-combustibility test of cast aluminum-ceramic foam for marine
applications was included inside the paper. The composite foam was
prepared by the gas injection method, consisting in direct injection of
gas into liquid metal. Foams with closed and open cells were examined.
The foams were foaming with foaming gas consisting of nitrogen or air.
This work is one of elements of researches connected with description of
properties of composite foams. In author's other works acoustic
properties of these materials will be presented.

Abstract

The paper presents the results of thermoanalytical studies by
TG/DTG/DTA, FTIR and GC/MS for the oil sand used in art and precision
foundry. On the basis of course of DTG and DTA curves the characteristic
temperature points for thermal effects accompanying the thermal
decomposition reactions were determined. This results were linked with
structural changes occurred in sample. It has been shown that the
highest weight loss of the sample at temperatures of about 320°C is
associated with destruction of C-H bonds (FTIR). In addition, a large
volume of gases and high amounts of compounds from the BTEX group are
generated when liquid metal interacts with oil sand. The results show,
that compared to other molding sands used in foundry, this material is
characterized by the highest gaseous emissions and the highest
harmfulness, because benzene emissions per kilogram of oil sand are more
than 7 times higher than molding sand with furan and phenolic binders
and green sand with bentonite and lustrous carbon carrier.

Abstract

Grain refining and modification are common foundry practice for
improving properties of cast Al-Si alloys. In general, these types of
treatments provide better fluidity, decreased porosity, higher yield
strength and ductility. However, in practice, there are still some
discrepancies on the reproducibility of the results from grain refining
and effect of the refiner’s additions. Several factors include the
fading effect of grain refinement and modifiers, inhomogeneous dendritic
structure and non-uniform eutectic modification. In this study, standard
ALCAN test was used by considering Taguchi’s experimental design
techniques to evaluate grain refinement and modification efficiency. The
effects of five casting parameters on the grain size have been
investigated for A357 casting alloy. The results showed that the
addition of the grain refiner was the most effective factor on the grain
size. It was found that holding time, casting temperature, alloy type
and modification with Sr were less effective over grain refinement.

Abstract

This paper presents the idea of increasing the effectiveness of slag
decopperisation in an electric furnace in the "Głogów II" Copper Smelter
by replacing the currently added CaCO3with a less energy-intensive
technological additive. As a result of this conversion, one may expect
improved parameters of the process, including process time or power
consumption per cycle. The incentives to optimize the process are the
benefits of increasing copper production in the company and the growing
global demand for this metal. The paper also describes other factors
that may have a significant impact on the optimization of the copper
production process. Based on the literature analysis, a solution has
been developed that improves the copper production process. The benefits
of using a new technology additive primarily include increased share of
copper in the alloy, reduced production costs, reduced amount of power
consumed per cycle and reduced time it takes to melt. At the conclusion
of the paper, the issues raised are highlighted, stressing that
mastering the slag slurry process in electric furnaces requires
continuous improvement.

Abstract

The results of research on the effect of the type of cooling agent used
during heat treatment and thermal-chemical treatment on the formation of
temperature gradient and stress-deformation distribution in cast
pallets, which are part of furnace accessories used in this treatment,
are disclosed. During operation, pallets are exposed to the effect of
the same conditions as the charge they are carrying. Cyclic thermal
loads are the main cause of excessive deformations or cracks, which
after some time of the cast pallet operation result in its withdrawal
due to damage. One of the major causes of this damage are stresses
formed under the effect of temperature gradient in the unevenly cooled
pallet construction. Studies focused on the analysis of heat flow in a
charge-loaded pallet, cooled by various cooling agents characterized by
different heat transfer coefficients and temperature. Based on the
obtained temperature distribution, the stress distribution and the
resulting deformation were examined. The results enabled drawing
relevant conclusions about the effect of cooling conditions on stresses
formed in the direction of the largest temperature gradient.

Abstract

This paper presents the impact of microwave penetration depth on the
process of heating the moulding sand with sodium silicate. For each
material it is affected by: the wavelength in vacuum and the real and
imaginary components of the relative complex electrical permittivity
εrfor a selected measurement frequency. Since the components are not
constant values and they change depending on the electrical parameters
of materials and the frequency of the electromagnetic wave, it is
indispensable to carry out laboratory measurements to determine them.
Moreover, the electrical parameters of materials are also affected by:
temperature, packing degree, humidity and conductivity. The measurements
of the dielectric properties of moulding sand with sodium silicate was
carried out using the perturbation method on a stand of waveguide
resonance cavity. The real and imaginary components of the relative
complex electrical permittivity was determined for moulding sand at
various contents of sodium silicate and at various packing degrees of
the samples. On the basis of the results the microwave penetration depth
of moulding sand with sodium silicate was established. Relative
literature contains no such data that would be essential to predicting
an effective process of microwave heating of moulding sand with sodium
silicate. Both the packing degree and the amount of sodium silicate in
moulding sand turned out to affect the penetration depth, which directly
translates into microwave power density distribution in the process of
microwave heating of moulding sand with sodium silicate.

Abstract

This article deals with the technology and principles of the laser
cutting of ductile cast iron. The properties of the CO2laser beam, input
parameters of the laser cutting, assist gases, the interaction of cut
material and the stability of cutting process are described. The
commonly used material (nodular cast iron - share of about 25% of all
castings on the market) and the method of the laser cutting of that
material, including the technological parameters that influence the
cutting edge, are characterized. Next, the application and use of this
method in mechanical engineering practice is described, focusing on
fixing and renovation of mechanical components such as removing the
inflow gate from castings with the desired quality of the cut, without
the further using of the chip machining technology. Experimental samples
from the nodular cast iron were created by using different technological
parameters of laser cutting. The heat affected zone (HAZ), its width,
microstructure and roughness parameter Pt was monitored on the
experimental samples (of thickness t = 13 mm). The technological
parameters that were varied during the experiments included the type of
assist gases (N2and O2), to be more specific the ratio of gases, and the
cutting speed, which ranged from 1.6 m/min to 0.32 m/min. Both
parameters were changed until the desired properties were achieved.

Abstract

The aim of this paper was to attain defect free, pure copper castings
with the highest possible electrical conductivity. In this connection,
the effect of magnesium additives on the structure, the degree of
undercooling (ΔTα = Tα-Tmin, where Tα – the equilibrium solidification
temperature, Tmin – the minimum temperature at the beginning of
solidification), electrical conductivity, and the oxygen concentration
of pure copper castings have been studied. The two magnesium doses have
been investigated; namely 0.1 wt.% and 0.2 wt.%. A thermal analysis was
performed (using a type-S thermocouple) to determine the cooling curves.
The degree of undercooling and recalescence were determined from the
cooling and solidification curves, whereas the macrostructure
characteristics were conducted based on a metallographic examination. It
has been shown that the reaction of Mg causes solidification to
transform from exogenous to endogenous. Finally, the results of
electrical conductivity have been shown as well as the oxygen
concentration for the used Mg additives.

Abstract

The ecological meanings clearly indicates the need of reducing of the
concentration of the CO2in the atmosphere, which can be accomplished
through the lowering of the fuel consumption. This fact implies the
research for the new construction solutions regarding the reduction of
the weight of vehicles. The reduced weight of the vehicle is also
important in the case of application of the alternative propulsion, to
extend the lifetime of the batteries with the reduction of recharge
cycles. The use of cast alloy AlZnMgCu compliant of plastic forming
class 7xxx alloy, are intended to significantly reduce the weight of the
structures, while ensuring high strength properties. The wide range of
the solidification temperature, which is more than 150°C, characterizes
this alloy with a high tendency to create the micro and macro porosity.
The study presents the relationship between the cooling rate and the
area of occurrence and percentage of microporosity. Then the results
were linked to the local tensile strength predicted in the simulation
analysis. The evaluation of the microporosity was performed on the basis
of the CT (computed tomography) and the analysis of the alloy
microstructure. The microstructure analysis was carried out on test
specimen obtained from the varying wall thickness of the experimental
casting. The evaluation of the mechanical properties was prepared on the
basis of the static tensile test and the modified low cycle fatigue test
(MLCF).

Abstract

In this paper, crushability of foundry sand particles was studied. Three
kinds of in-service silica sands in foundry enterprises selected as the
study object, and foundry sand particles were subjected to mechanical
load and thermal load during service were analyzed. A set of methods for
simulating mechanical load and thermal load by milling and thermal-cold
cycling were designed and researched, which were used to characterize
the crushability for silica sand particles, the microstructure was
observed by SEM. According to the user’s experience in actual
application, the crushability of Sand C was the best and then Sand B,
the last Sand A. The results indicated that mechanical load, thermal
load and thermal-mechanical load can all be used to characterize the
crushability of foundry sand particles. Microscopic appearances can
qualitatively characterize the crushability of foundry sand particles to
a certain extent, combining with the additions and cracks which are
observed on the surface.

Abstract

Forecasting and analysis SWOT are helping tools in the business
activity, because under conditions of dynamic changes in both closer and
more distant surroundings, reliable, forward-looking information and
trends analysis are playing a decisive role. At present, the ability to
use available data in forecasting and other analyzes according with
changes in business environment are the key managerial skills required,
since both forecasting and SWOT analysis are a integral part of the
management process, and the appropriate level of forecasting knowledge
is increasingly appreciated. Examples of practical use of some
forecasting methods in optimization of the procurement, production and
distribution processes in foundries are given. The possibilities of
using conventional quantitative forecasting methods based on econometric
and adaptive models applying the creep trend and harmonic weights are
presented. The econometric models were additionally supplemented with
the presentation of error estimation methodology, quality assessment and
statistical verification of the forecast. The possibility of using
qualitative forecasts based on SWOT analysis was also mentioned.

Abstract

The paper presents validation tests for method which is used for the
evaluation of the statistical distribution parameters for 3D particles’
diameters. The tested method, as source data, uses chord sets which are
registered from a random cutting plane placed inside a sample space. In
the sample space, there were individually generated three sets
containing 3D virtual spheres. Each set had different Cumulative
Distribution Function (CDF3) of the sphere diameters, namely: constant
radius, normal distribution and bimodal distribution as a superposition
of two normal distributions. It has been shown that having only a chord
set it is possible, by using the tested method, to calculate the mean
value of the outer sphere areas. For the sets of data, a chord method
generates quite large errors for around 10% of the smallest nodules in
the analysed population. With the increase of the nodule radii, the
estimation errors decrease. The tested method may be applied to foundry
issues e.g. for the estimation of gas pore sizes in castings or for the
estimation of nodule graphite sizes in ductile cast iron.

Abstract

Among the copper based alloys, Cu-Al-X bronzes are commonly used as mold
materials due to their superior physical and chemical properties. Mold
materials suffer from both wear and corrosion, thus, it is necessary to
know which one of the competitive phenomenon is dominant during the
service conditions. In this study, tribo-corrosion behavior of
CuAl10Ni5Fe4 and CuAl14Fe4Mn2Co alloys were studied and electrochemical
measurements were carried out using three electrode system in 3.5 % NaCl
solution in order to evaluate their corrosion resistance. In
tribo-corrosion tests, alloys were tested against zirconia ball in 3.5 %
NaCl solution, under 10N load with 0.04 m/s sliding speed during 300 and
600 m. The results indicate that (i) CuAl10Ni5Fe4 alloy is more
resistant to NaCl solution compared to CuAl14Fe4Mn2Co alloy that has
major galvanic cells within its matrix, (ii) although CuAl10Ni5Fe4 alloy
has lower coefficient of friction value, it suffers from wear under dry
sliding conditions, (iii) as the sliding distance increases, corrosion
products on CuAl14Fe4Mn2Co surface increase at a higher rate compared to
CuAl10Ni5Fe4 leading to a decrease in volume loss due to the lubricant
effect of copper oxides.

Abstract

The article presents an example of finishing treatment for aluminum
alloys with the use of vibration machining, with loose abrasive media in
a closed tumbler. For the analysis of selected properties of the surface
layer prepared flat samples of aluminum alloy PA6/2017 in the state
after recrystallization. The samples in the first stage were subjected
to a treatment of deburring using ceramic media. In a second step
polishing process performed with a strengthening metal media. In
addition, for comparative purposes was considered. only the case of
metal polishing. The prepared samples were subjected to hardness tests
and a tangential tensile test. As a result of finishing with vibratory
machining, it was possible to remove burrs, flash, rounding sharp edges,
smoothing and lightening the surface of objects made. The basic
parameters of the surface geometry were obtained using the Talysurf CCI
Lite - Taylor Hobson optical profiler. As a result of the tests it can
be stated that the greatest reduction of surface roughness and mass loss
occurs in the first minutes of the process. Mechanical tests have shown
that the most advantageous high values of tensile strength and hardness
are obtained with two-stage vibration treatment, - combination of
deburring and polishing. Moreover the use of metal media resulted in the
strengthening of the surface by pressure deburring with metal media.